Such a controversial symbol, yet, so popular. I was first introduced to the pentagram via Heavy Metal where it was basically a symbol of rebellion & everyone would whisper how Satanic it was. Today, I'm much wiser to its meanings & find that it has rich history. Of course, I still listen & play my Metal.
The first known usage of the symbol dates back 3,000 B.C. in ancient Sumer. It was a pictogram for the word "Ub" & meant corner, angle, nook; small room, cavity, hole; pitfall. Sumerians used it in its inverted form.
In Babylon, it was used to represent forward, backwards, left, right & above. These had astrological meaning as well, as in the five known planets at that time: Jupiter, Mercury, Mars, Saturn & Venus (formally known as Ishtar) "Queen of Heaven". Let's not forget the 5 senses as well.
The Egyptians used it as their symbol of the underground womb, from which, all life came from. Surprisingly the Celts used it as well with the same similar meaning.
For the Druids, it represented the Godhead.
In Greece, it was used by Pythagoras & its meanings were numerous. It represented health & symbolized the Greek goddess of health, Hygieia. They used it inverted. It symbolized the Pentemychos doctrine. It was used to represent the place where pre-cosmic offspring was put into order for the appearance the cosmic order. Mathematical perfection is what he saw in it's shape. The Golden Mean. Plato considered it the symbol of heaven.
It was also connected to the goddess Kore (Hecate & Persephone), who's symbol was an apple. The apple is also a symbol of health. If you cut an apple transversally in half, you'll see a pentagram.
Add to it the five classical elements: water, earth, idea, heat(fire), air. It is the hiding place of the golden mean.
In Hinduism, the god Shiva is know as Panchanana (five faced). The pentagram is used even now as a symbol of this god.
The Hebrew called it the Seal of Solomon & it was the seal of Jerusalem. Later on, for Jews, it would come to symbolize the five books Pentateuch & truth.
For the Chinese, it was Wu Xing & its meaning was fire, earth, metal, water, wood.
It was the Roman symbol of the building trades.
Man in the Microcosm for Hermetics.
In Medieval times it was used to ward off demons. It was called the Endless Knot & was a symbol of truth.
In Christianity it was used to symbolize the five wounds of Christ & it was also used as the symbol for Epiphany feast. Gnostics called it Blazing Star & it represented the mystical. The Mormons used it upright & inverted. For them its connection is the Morning Star.
Knights used this symbol as well. For them it was five virtues: generosity, courtesy, chastity, chivalry & piety.
The Bahai Faith it is called Haykal(temple) & is representative of the body (head, two arms, two legs). It is the symbol of their religion.
Rosicrucian usage is humanity reborn & inner mystery.
For Romas (Gypsies) it is the Pentacle of the Virgin or Star of Knowledge.
When upright it is used in freemasonry to symbolize the Master of the Lodge.
The Order of the Eastern Star it represents the Star of Bethlehem. It points down to symbolize the light shining down from heaven to Earth. It also symbolizes five biblical heroines.
The inverted pentagram was first given a negative connotation by Eliphas Levi. His words:
"A reversed pentagram, with two points projecting upwards, is a symbol of evil and attracts sinister forces because it overturns the proper order of things and demonstrates the triumph of matter over spirit. It is the goat of lust attacking the heavens with its horns, a sign execrated by initiates."
Satanist usually use the inverted version to represent the two horns coming off the goat head, which is usually inside the pentagram, & the three points down is rejection of the Holy Trinity.
In modern Paganism & particularly Wicca, it is used as the five classical elements with the exception that idea is replaced with spirit. The inverted, no circle form is used to symbolize a 2nd degree in more traditional Wicca. The circle has come to represent unity, wholeness, infinity, the Goddess & protection.
The Church & School of Wicca says it symbolizes 1) The Wiccan Rede, 2) The Law of Attraction, 3) Harmony & Serenity, 4) Power through knowledge & 5) Progressive Reincarnation. With the center symbolizing deity.
In Thelema the inverted pentagram represents the dissention of spirit into matter. Pointing up it represents the transcendence of the New Aeon.
Other Paganspace discussions on the Pentagram: here,